1. Field of the Invention
The invention relates in general to information retrieval and more particularly to query-based information retrieval.
2. Description of the Related Art
A query-concept learning approach can be characterized by the following example: Suppose one is asked, “Are the paintings of Leonardo da Vinci more like those of Peter Paul Rubens or those of Raphael?” One is likely to respond with: “What is the basis for the comparison?” Indeed, without knowing the criteria (i.e., the query concept) by which the comparison is to be made, a database system cannot effectively conduct a search. In short, a query concept is that which the user has in mind as he or she conducts a search. In other words, it is that which the user has in mind that serves as his or her criteria for deciding whether or not a particular object is what the user seeks.
For many search tasks, however, a query concept is difficult to articulate, and articulation can be subjective. For instance, in a multimedia search, it is difficult to describe a desired image using low-level features such as color, shape, and texture (these are widely used features for representing images [17]). Different users may use different combinations of these features to depict the same image. In addition, most users (e.g., Internet users) are not trained to specify simple query criteria using SQL, for instance. In order to take individuals' subjectivity into consideration and to make information access easier, it is both necessary and desirable to build intelligent search engines that can discover (i.e., that can learn) individuals' query concepts quickly and accurately.